Today, individuals are getting computer images on a number of different types of displays. For example, individuals are viewing images on their personal computers (PCs), personal digital assistants (PDAs), cell phones, and whole host of other devices. However, the displays on each of these devices are different sizes. Therefore, the highest resolution image that each could display may be different. It would be advantageous to be able to display the highest level resolution image for any device even though only a portion of the image fits the display window. The feature of panning allows the user to see other regions, and multiresolution for zooming enables display of the entire image for any window size.
For instance, it is quite common for a doctor to review images and make diagnosis recommendations based on that review. Currently, doctors are able to specify regions of interest in a particular image to view. However, doctors would like to be able to select a specific part of an image and get that portion of the image at a greater resolution. Being able to obtain a larger image may not be advantageous if the image is not lossless, because a doctor may have to rely on details appearing in the image to make a diagnoses. Therefore, it would be advantageous to send digital images so that selective regions of interest in images may be displayed losslessly and at varying resolution levels.
Today, images are transmitted in a compressed form. There are many compression techniques that are well known in the art. The most well-known ones are JPEG, GIF, PNG, and JPEG-2000. For lossless compression, the JPEG standard uses predication coding (DPCM), and for progressive viewing, the hierachal mode of JPEG depends on coding of prediction (or difference) error images. For more information, see W. B. Pennebar and J. L. Mitchell, “JPEG: Still Image JA Compression Standard,” Van Norstrand Reihold Publisher, N.Y., 1993. As another example, see U.S. Pat. No. 4,749,983, entitled “Compression of Multi-level Signals.” Furthermore, the MPEG standards (MPEG 1, 2 and 4) sets forth one coding standard, that includes the coding of P frames (or residual frames). This is essentially the same as coding prediction error images (after motion estimation and compensation are performed).